Protective device for stud driving tools



Sept. 13, 1960 w. E. SCHULZ PROTECTIVE DEVICE FOR STUD DRIVING TOOLS Filed Aug. 2l 1956 2 Sheets-Sheet 1 FIG. 1:1

I INVENTOR. WALTER E scHl Lz' ATTORNEY:

Sept. 13, 1960 w. E. SCHVULZ 1 2,952,020

PROTECTIVE DEVICE FOR STUD DRIVING TOOLS Filed Aug. 21, 1956 2 Sheets-Sheet 2 \twmwmw 35' a as FIG. 5 V

L-l I I Y I f 1 L a! as l I J 2 FIG. 6a.

FIG. 6

FIG. 7

INVENTOR WALTER E SCHULZ ATTORNEYS PROTECTIVE DEVICE FOR STUD DRIVING TOOLS Walter E. Schulz, Goethestr. '44, Wulfrath, Germany Filed Aug. 21, 1956, Ser. No. 605,406

Claims priority, application Germany Aug. 23, I955 Claims. (Cl. 1--"44.'5)

The present invention relates to a tool for driving studs into solid. bodies by means of the force of highly compressed gases. The invention is concerned more particularl-y with a protective device serving to protect the person operating the tool and other persons standing nearby against flying particles or studs reemerging near the point at which the stud was installed in the surface. Experiencehas shown that when driving studs into surfaces the studs sometimes follow a curved trajectory in the material and reemerge from the material near the point of the installation. The object of the invention is to provide. a protective device enabling studs to be installed in corners. Inorder to eliminate the danger caused by: flying particles or reemerging studs the stud driving tools are, as a rule, equipped with plateor cup-like protective devices mounted onthe barrel of the device and covering the areaaround the point where the stud is driven into the surface. However, the disadvantage of these. protective devices is that they are in the way wherr a stud is to be installed near a corner. To enable studs. to. be driven into surfaces near corners the protective. devices were designed so as to permit the barrel to be. positioned either concentrically or eccentricall-y with respect to. the protective device. In: this way' it is made possible for studs. to be driven into surfaces near corners when the. barrel is eccentricall-y' positioned, but at the same: time the danger arises that the tool is used with eccentrically positioned protective device also when studs are; to be driven into straight surfaces. Instructions not to. use the stud: driving tool' with eccentrically positioned protective: device when studs are not to be installed near corners will. be of: little avails Forgetfulness or negligence on; the part of the operators will often lead to these instructions being disregarded. In addition, whenthe protective: device. is eccentrically positioned the point at which. the. barrel is engaged with the surface can be better observed, which. is a further incentive to the operator to disregard the instruction and to drive studs into straight surfaces when the protective device is eccentricall y positioned. This is particularly dangerous because in this case the operator will. hold histool in sucha way that the face will, be on that sideof the tool which offers less protection. by reason of the protective device having been eccentrically positioned.

Although these. dangers have been known for some considerable: time no=practicable proposal has as yetbeen madev to design the protective. device in such a manner that: the driving of studs intosurfaces near corners is possible while the use of a tool with eccentricall'y positioned protective device for the driving of studs into straightsurfaces. is reliably prevented; The present invention attains. this: purpose by an elastic force which positionsrtherbarreli concentrically with respect to thesur face-y coveredby' the tool and which ensures that the eccentric position can only be achieved it external force acting against the elastic force acts. upon. the. profestive. device; .a This. compels the operaton'to achieve the eccentric position by turning or moving a part of the 2,952,020 Patented Sept. 13, 1960 protective device against the pressure of the spring, this eccentric position being maintained only as long as the Wall adjacent or vertical to the surface receiving the stud prevents the tool from returning into the concentric position. Whenv the firing has taken place and the tool is lowered the concentric position is restored under the influence of thespring. It is advisable to provide a catch which arrests the device in the position in. which the barrel is positioned concentrically with respect to the surface coveredso that when studs are to be installed in corners the catch has to be removed first.

Devices have become known where the protective plate contains an eccentrically located circular aperture with a rotatable disc on which the barrel is eccentrically mounted. With devices of this type it is possible by turning the disc to move the barrel optionally to the center or near the edge of the protective plate. In modifying such a device in accordance with the invention a helical spring may be provided which is activated when the barrel is turned away from its concentric position with respect to the protective plate. Moreover, devices are known where two segments of a bellor cup-like protective cap can be rotatably moved against each other. With this type, too, a helical spring may be provided which is activated when one of the two segments is turned relatively to the other segment so that the flattening of one segment permits studs to be fired into corners. Furthermore, the barrel may be slidable in a covered slot provided in the protective plate, this sliding movement activating a spring when the barrel ismoved from a position concentric with respect to the protective late.

p A particularly advantageous element in the design of the object of the present invention is that a part of the protective plate can be moved upwardly by means of a hinge; this movement having to be undertaken against the influence of an elastic force. A similar spring-loaded locking device arrests the upwardly movable part 1n its neutral position so that it cannot move upwardly either when the toolis engaged with the surface in a slant or under the influence of forces caused by the firing of the tool. A safe method of arresting the movable partcan be designed, for example, by providing a hinge which isguided in slots inserted in the immovable part, at the same time providing for stops which guide the movable part in such a manner that the pins of the hinge move in the sl ots against the action of a: spring. In this connection a-further stop can be provided which arrest-s the movable part in its neutral" position, the upward movement of the movable part having to be initiated by first pullingit out against the force of the said spring; after which it canbe moved upward.

Examples for the construction of the object of the invention aresh'ownin-Figs. 1 to 7'.

Fig. 1 shows a plan view of an embodment' of a proteetive shield in accordance with the invention in which the barrel of the stud-driving device is positioned in an eccentric disc;

Fig. l a a sectional view taken thr-u II of Fig. I;

Fig: is .a' plan view of a further embodiment of a protective shield in accordance with the invention, con, sisting' of a. bellor cup-shaped protective cap divided into tow segments rotatably movable relative to each other;

Fig. 2a is a sectional view taken thru H--II of Fig. 2;

Fig. 3 is aplan view of a stillfurther embodiment of a protective shield in accordance with the invention with the barrel: ofthe-st-ud-driving device being mounted on aslidable plate; I

High 3b-'is a. sectional view takenthrough III-III of Fig. 3

Fig. 4 is a side elevation of a still further embodiment of a protective shield in accordance with the invention, having two parts pivotally mounted with respect to each other;

Fig. is a side elevation of the embodiment shown in Fig. 4 with one of the pivotal parts pivoted upwardly;

Fig. 6 is a plan view of the embodiment shown in Fig. 4; and

Fig. 6a is a sectional view taken through VI-VI of Fig. 6;

Fig. 7 is a side elevation of a still further embodiment of a protective shield in accordance with the invention, having two hinged parts;

Fig. 7b is a plan view of the embodiment shown in Fig. 7.

With the design shown in Fig. 1 an eccentrically positioned circular aperture is provided in the square protective plate 1, a disc 2 having been rotatably inserted in the aperture. The barrel 3 is eccentrically mounted on the disc 2. A suitably covered circular groove 4 contains a helical spring 5 whose one end is connected to the pin 6 mounted on plate 1 and whose other end is connected to the pin 7 mounted on plate 2. If the disc 2 is turned from the position as indicated in Fig. 1, Where the barrel 3 is in the center of the plate 1, in the direction of the arrow 8, the spring 5 is stretched. This spring reaches its maximum tension (7' in Fig. 1) when the barrel is in position 3' after a half turn of the disc 2. When the plate is no longer maintained in this position by an external force, it returns to the original position indicated in the figure, so that the barrel is once again concentrically positioned with respect to the protective plate. In this position it can be additionally arrested by a catch 9 which is conveniently spring-loaded, so that before turning the protective plate this catch has to be removed by means of a button 10 which protrudes from the protective plate. It goes without saying that instead of the helical spring as indicated in the said figure any other type of spring can be employed to eifect the return to the original position, for example a loop spring as specified in greater detail in the following example.

The protective device depicted in Fig. 2 consists in a known manner of two segments 12 and 13 which are rotatably movable against each other. If the segment 13 is turned in the direction of the arrow .14, the plane surface 15 of segment 12 is free and the tool can be used to drive studs into corners. The invention provides that by turning the segment 13 against segment 12, the loop spring .16 is activated. One end of the loop spring 16 is mounted on segment 13 at point 17 and the other end is mounted on segment 12 at point 18. In this case, too, a catch can be provided in the neutral position where the barrel 3 is concentrically positioned with respect to the covered area. This catch is schematically inidcated by the hook 19, which engages with a notch 20 of segment 12, is rotatably connected to segment 13, and is caused to engage with the notch by means of a spring 21.

Fig. 3 shows a protective plate 22 which is slidably connected to the barrel 3. For this purpose the plate 22 has a slot 23 which is covered by .a plate 24 on which the barrel 3 is mounted. The plate 24 is guided by the rails 25. When moving the plate 24 in the direction of the arrow 26 a spring, for example the tension spring 27, is activated. A catch 28 can be provided similar to the embodiment of the invention as per Fig. 1, which catch holds the plate 24 in its neutral position and is disengaged by the button 29 which protrudes from the plate 22.

With the design depicted in Figs. 4, 5, and 6 the barrel 3 is firmly or rotatably connected to plate 31. The plate 31 has two lateral slots 32 in which pins 33 are guided. The upwardly movable part 34 is connected to these pins. The pins 33 are under the action of'ten sion springs 35 which act both on pin 33 and on pin 36 mounted on plate 31. On the upper side of plate 31 stops 37 are mounted at either side by means of welding or riveting which stops protrude a little from plate 31 so that, when movable part 34 is moved upwardly, its webs engage with these stops. This automatically achieves a guiding effect because, by moving part 34 upwardly, the studs 33 move to the right, thus activating the springs 35. The plate 31 is moreover provided with one or more stops 39, which protrude a little from the edge of plate 31 adjacent to the movable part 34. These stops maintain part 34 in its neutral position so that it is prevented from moving upwardly under the influence of any forces acting upon it from below. Part 34 is moved upwardly by first pulling part 34 out in the direction of the arrow 40 and then moving it upwardly in the direction of arrow 41. In the position of part 34 depicted in Fig. 5 the pins 33 are close to the right-hand ends of slots 32 so that the springs 35 are under tension. The webs 38 engage with the stops 37 so that, as soon as part 34 ceases to be maintained in its upward position, it returns to its neutral position under the influence of the springs 35 as shown in Figs. 4 and 6 and is arrested in this position by means of stop 39. The edges 42 of plate 31 and of part 34 which form a joint when part 34 is in its neutral position have been suitably shaped to overlap so as to prevent the entry of fragments through the protective plate.

In the embodiment of the object of the invention illustrated by Fig. 7 an upwardly movable part 45 is connected to the protective plate 44 mounted on barrel 3, similar to Figs. 4 to 6. Instead of the link hinge used in Figs. 4 to 6 a common double-leaf hinge 46 which suitably covers the whole joint has been used. A locking bar 48 is slidably connected to plate 44 by means of straps 47. By means of a spring 49 the bar is moved to the right into the depicted position in which it arrests part 45 in its original position. To be able to move part 45 upwardly, the bar 48 has to be pulled back against the action of spring 49, after which part 45 can be moved upwardly. In this position it is under the action of bar 48 whichas shown-is designed so as to force part 45 into its original position from any other position.

The mounting of the elastic force means and the stops can be made in a manner different from that shown in the figures. The essential feature is that in any case when the barrel is not positioned concentrically with respect to the area covered, an elastic force is active which achieves a position wherein the barrel is concentrically located with respect to the area covered. After a stud has been fired into a corner by means of an eccentric protective device it is therefore impossible to neglect the restoration of the concentric position because this is done automatically. If the process of firing a stud into a corner is to be repeated, the eccentric position has to be achieved and the catch disengaged every time. A special advantage of the designs shown in Figs. 4 to 7 is that the upwardly moved part 34 or 45 engages with the wall standing vertical to the surface into which the stud is to be driven when firing into a corner and thus covers part of the latter wall as well, whereby protection is achieved against any fragments projected from this source. The device shown in Figs. 4 to 6 can easily be designed so that, when studs are to be fired into salient corners and part of the protective device would not cover any surface, part 34 can be moved downwardly, whereby the protective device would be effective on both sides of the corner.

All the structural elements, like springs, stops etc., can naturally be housed in non-removable box-like or otherwise shaped metal casings so that the operator cannot remove the springs, etc. and thus render the protective device inefiective.

What I claim is:

1. In a device for driving studs into solid bodies having a barrel through which the stud is shot and a protective shield surrounding the muzzle of the barrel, the improvement which comprises said protective shield being defined essentially by two parts movable with respect to each other between a first position with said barrel concentrically positioned with respect to the protective shield defined by said parts in said first position and a second position with said barrel eccentrically positioned with respect to the protective shield defined by said parts in said second position, and means resiliently biasing said parts to said first position.

2. Improvement according to claim 1, including manually releasable catch means for locking said parts in said first position, said manually releasable catch means being actuated to lock said parts in said first position by movement of the parts to the first position.

3. Improvement according to claim 1, in which one of said parts comprises a plate defining an eccentric aperture, the other of said parts comprising a circular disc rotatably fitted in said aperture, having said barrel eccentrically connected thereto, and in which said means biasing said parts comprises spring means, resiliently biasing said disc to rotate to a position with said barrel con centrically positioned with respect to said plate.

4. Improvement according to claim 1, in which said parts comprise two unequal sphere segments rotatably connected with respect to each other to define a hemisphere in said first position with said barrel concentrically positioned therein connected to the larger of said spheres, and with said sphere segments coinciding in said second position, and in which said means resiliently biasing said parts comprises spring means resiliently biasing said sphere segments to rotate to said first position.

5. Improvement according to claim 1, in which one of said parts comprises a first plate defining a longitudinal slot extending from the center thereof toward one side thereof, the other of said parts comprising a second plate having said barrel connected thereto and mounted on said first plate for longitudinal sliding motion coaxially with the longitudinal axis of said slot between said first position with said barrel concentrically positioned with respect to said first plate and the muzzle of said barrel registering with said slot and said second position with said barrel eccentrically positioned with respect to said first plate and the muzzle of said barrel registering with said slot, said second plate having sufficient length to cover said slot in any position of motion thereof.

6. Improvement according to claim 5, including manually releasable catch means for locking said plate in said first position.

7. Improvement according to claim 1, in which said parts comprise a first plate having said barrel connected thereto and a second plate hinged to said first plate for pivoting between said first position in a common plane with said first plate, forming a continuation thereof, and said second position pivoted upwardly alongside said first plate.

8. Improvement according to claim 7, in which said means resiliently biasing said parts comprises a locking bar slidably mounted on said first plate for sliding transversely across said hinge, and spring means resiliently biasing said locking bar for sliding movement across said hinge.

9. Improvement according to claim 1 in which said parts comprise a first plate having said barrel connected thereto, a second plate having web extensions with pivot pins along opposite sides thereof positioned alongside said first plate for pivoting between said first position in a common plane with said first plate forming a com tinuation thereof, and said second position pivoted upwardly alongside said first plate, with said web extensions straddling said first plate and said pins extending in longitudinal slots defined in the sides of said first plate, and in which said means resiliently biasing said parts comprises spring means resiliently biasing said pins for movement in said slots in a direction toward the edge of said first plate opposite said second plate.

10. Improvement according to claim 9, including a flat stop plate connected to said first plate, extending past the upper edge of said first plate adjacent said second plate and two stop means extending past the upper edge of said first plate above each of said web extensions.

References Cited in the file of this patent UNITED STATES PATENTS 

